Nonlinear voltage error analysis and control of resonant high precision converter

Abstract

The current nonlinear distortion of power converter can cause motion trajectory error and positioning error of motor, and affect the nano motion and positioning accuracy of ultra-precision system. The resonant pole-based dual buck soft-switching power converter (RPDBSPC) topology does not​ suffer current distortion caused by blanking time, and can support the high-frequency operation. It is suitable for the field of high dynamic and high-precision motion control. In order to realize the low nonlinear distortion current, the dual buck soft-switching topology should possess high linear output characteristics, and its nonlinear voltage error needs to be suppressed. This paper analyzes the operation principle of resonant power converter, and establishes its state space average model. Based on this, the nonlinear voltage error related resonant process of soft-switching topology is researched. Combined with the resonant equivalent circuit under unbalanced voltage sharing condition and the nonlinear characteristics of switching output capacitance, the expressions of nonlinear voltage error and zero voltage time are deduced, and a nonlinear voltage error suppression method based on zero voltage time control is proposed, which effectively reduces the current nonlinear distortion of resonant power converter.

Keywords

• Dual buck soft-switching topology
• Nonlinear distortion
• Resonant commutation
• Voltage error
• Zero voltage time control